Nonvolatile semiconductor memory device with a plurality of memory blocks and a shared block decoder

ABSTRACT

A nonvolatile semiconductor memory device includes a memory cell array having multiple blocks each with a plurality of memory strings. Each memory string has multiple memory cells connected in series between first and second selection transistors. The device further includes a row decoder, a block decoder, first and second signal line groups, and a switch circuit. The row decoder has transfer transistors through which voltages are supplied to the selection transistors. The block decoder supplies a selection signal that indicates whether the first group or the second group has been selected. The first and second signal line groups are connected to the selection transistors of the memory strings that are in the respective first and second memory blocks of the first and second groups. The switch circuit connects the first and second signal line groups to the respective first and second memory blocks of the selected group.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of U.S. patent application Ser. No.15/984,834, filed on May 21, 2018, which is a continuation of U.S.patent application Ser. No. 15/497,928, filed on Apr. 26, 2017, now U.S.Pat. No. 10,008,268, granted on Jun. 26, 2018, which is a continuationof U.S. patent application Ser. No. 15/151,883, filed on May 11, 2016,now U.S. Pat. No. 9,666,284, granted on May 30, 2017, which is acontinuation of U.S. patent application Ser. No. 14/688,664, filed onApr. 16, 2015, now U.S. Pat. No. 9,368,213, granted on Jun. 14, 2016,which is a continuation of U.S. patent application Ser. No. 13/784,512,filed on Mar. 4, 2013, now U.S. Pat. No. 9,053,765, granted on Jun. 9,2015, which is based upon and claims the benefit of priority fromJapanese Patent Application No. 2012-209501, filed on Sep. 24, 2012, theentire contents of each of which are incorporated herein by reference.

FIELD

Embodiments relate to control circuits of semiconductor memory devices.

BACKGROUND

In recent years, a semiconductor memory in which memory cells arelaminated in stacked layers has been developed. This semiconductormemory provides high storage capacity at low cost. Increasedminiaturization and higher storage densities cause various problems suchas increasing sizes of related peripheral circuits in the memory deviceand associated wiring congestion as more memory cells are packed insmaller and smaller volumes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of an overall configuration of anonvolatile semiconductor memory device according to a first embodiment.

FIG. 2 illustrates a perspective view of a memory cell array accordingto the first embodiment.

FIG. 3 illustrates a cross-sectional view of a memory string accordingto the first embodiment.

FIG. 4 illustrates an equivalent circuit of the memory string accordingto the first embodiment.

FIG. 5 illustrates a schematic diagram of blocks, an Xfer_S, an Xfer_D,and a peripheral circuit according to the first embodiment.

FIG. 6 is a block diagram of a block decoder according to the firstembodiment.

FIG. 7 illustrates a circuit diagram of the block decoder according tothe first embodiment.

FIG. 8 illustrates a circuit diagram of a switch circuit according tothe first embodiment.

FIG. 9 illustrates a circuit diagram of a decoder part according to thefirst embodiment.

FIGS. 10A-10C are conceptual diagrams illustrating effects according tothe first embodiment: FIG. 10A illustrates an area occupied by a blockdecoder according to a comparative example; FIG. 10B illustrates an areaoccupied by the block decoder according to the first embodiment when asharing number n=2 is used; and FIG. 10C illustrates an area occupied bythe block decoder according to the first embodiment when the sharingnumber is n=4.

FIG. 11 is a table illustrating a reduction in the number of signalwirings according to the first embodiment.

FIG. 12 illustrates a circuit diagram of a decoder part according to asecond embodiment.

FIG. 13 is a conceptual connection diagram of blocks, an Xfer_S, anXfer_D, and a peripheral circuit according to a third embodiment.

DETAILED DESCRIPTION

Embodiments related to the present disclosure describe a nonvolatilesemiconductor memory device that allows the number of selection signalsrequired for selecting a memory block to be reduced. A nonvolatilesemiconductor memory device according to an embodiment includes a memorycell array, a row decoder, a block decoder, first and second signal linegroups, and a switch circuit. The memory cell array has a plurality ofmemory blocks and each of the memory blocks has a plurality of memorystrings. Each memory string has a plurality of memory cells connected inseries, a first selection transistor connected to a first end of theplurality of memory cells connected in series, and a second selectiontransistor connected to a second end of the plurality of memory cellsconnected in series. The row decoder has transfer transistors throughwhich voltages are supplied to the first and second selectiontransistors of the memory strings. The block decoder is configured tosupply a selection signal to the transfer transistors, the selectionsignal indicating which of the first group of memory blocks and thesecond group of memory blocks has been selected. The first signal linegroup is connected to the first and second selection transistors of thememory strings that are in first memory blocks of the first and secondgroups. The second signal line group is connected to the first andsecond selection transistors of the memory strings that are in secondmemory blocks of the first and second groups. The switch circuit isconfigured to connect the first signal line group to the first memoryblock of the selected group and the second signal line group to thesecond memory block of the selected group.

In the following, the present embodiment is explained with reference tothe drawings. In the following explanation, throughout all the drawings,common parts are indicated using common reference numerals or symbols.However, it should be noted that the drawings are schematic, and therelationship between a thickness and planar dimensions, the proportionof the thickness of each layer, and the like depicted are generallydifferent from actual dimensions and relative proportions. Therefore,the specific thickness and dimensions should be determined by takinginto consideration the following explanation rather than direct analysisof the drawing dimensions. Further, it should be readily understood thatactual parts have dimensional relationships and proportions that aredifferent than depicted in the drawings.

A nonvolatile semiconductor memory device according to the presentembodiment can reduce the total number of wirings from a block decoderBD to a transfer circuit (XFER_D and XFER_S) (also referred to atransfer transistors) by sharing multiple blocks with a single blockdecoder BD.

First Embodiment

FIG. 1 illustrates an example of an overall configuration of anonvolatile semiconductor memory device according to a first embodiment.As illustrated in FIG. 1, the nonvolatile semiconductor memory deviceaccording to the first embodiment is configured from a memory cell array10 (1st Plane-Nth Plane in the drawing) and a peripheral circuit 20capable of controlling the memory cell array 10.

As will described later, each of the 1st Plane-Nth Plane is capable ofholding data and is provided with a plurality of laminated type memorycells MC stacked in a direction normal to a semiconductor substrate.

The peripheral circuit 20 includes a control unit controlling the 1stPlane-Nth Plane and a voltage generating circuit outputting variousvoltages when data writing, reading, erasing, and the like areperformed. The control part and the voltage generating circuit areconfigured by various MOS transistors and signal lines and contact plugsCP supplying voltages to the MOS transistors. These MOS transistors,signal lines, contact plugs CP, and the like, are also generallyarranged under the memory cell array 10.

Next, a plan view of the 1st Plane is explained. The other planes (2ndPlane 1-Nth Plane) have the same configuration as the 1st Plane andtherefore their explanation is omitted.

As illustrated in the drawing, the 1st Plane is provided with MAT11-0and MAT11-1 (either of which may be simply referred to as MAT11 when itis not required to distinguished one from the other), an XFER_S, anXFER_D, a column decoder COL (COL in the drawing) and a block decoder BD(BD in the drawing), the XFER_S and the XFER_D being arranged betweenthose MAT11.

Each of MAT11-0 and MAT11-1 is provided with a plurality of memorystrings MS. In a manner penetrating through these memory strings MS,word lines WL0-WL3 (referred to as the first signal line group in thefollowing) and word lines WL4-WL7 (referred to as the second signal linegroup in the following) are formed extending in a first direction, and aplurality of bit lines BL (not illustrated in the drawings) are formedextending in a second direction.

An end of the word lines WL0-WL3 is connected to the XFER_S and an endof the word lines WL4-WL7 is connected to the XFER_D. That is, the wordlines WL that penetrate through the MAT11 are arranged in a comb shape.

The XFER_D and the XFER_S are configured from a plurality of MOStransistors and select one of the memory strings MS in the MAT11.Specifically, upon receiving a control signal from the block decoder BD,the XFER_D and the XFER_S are capable of selecting a memory string MSthat is a read, write or erase operation target.

The block decoder BD switches the MOS transistors in the XFER_S and theXFER_D on and off and selects the memory string MS of a write, read orerase operation target from the plurality of memory strings MS.

The column decoder COL selects a bit line BL (not illustrated in thedrawings).

<Cross-Sectional View of Memory Cell Array 10>

FIG. 2 illustrates a three-dimensional perspective view of a structureof the memory strings MS that configure the 1st Plane. The structure ofthe 1st Plane illustrated here is the same as that of the 2nd Plane-NthPlane, and therefore the explanation is given here with a focus on the1st Plane as an example.

As illustrated in FIG. 2, in a plane formed by the first direction andthe second direction, columnar semiconductor layers SC are formed in amatrix form (5×4, as depicted). A plurality of the semiconductor layersSC are formed on a semiconductor layer BG along a third direction thatis orthogonal to the first direction and the second direction. Further,semiconductor layers SC that are mutually adjacent to each other alongthe second direction are joined via a joint part JP in the semiconductorlayer BG. That is, the semiconductor layers SC that are mutuallyadjacent to each other form a U-shaped memory string MS via the jointpart JP.

Therefore, semiconductor layers SC11, SC12, SC13, and SC14 aresequentially formed in the second direction. As depicted, thesemiconductor layers SC11 and SC12 are joined by a joint part JP11 andthe semiconductor layers SC13 and SC14 are joined by a joint part JP12.Along the first direction, other groups of semiconductor layerscontaining, for example, semiconductor layers SC21 and SC22 andsemiconductor layers SC23 and SC24 that are formed in a manner adjacentto the semiconductor layers SC11, SC12, SC13 and SC14 also have asimilar configuration and therefore their explanation is omitted.Further, in the present example embodiment, m=5 and n=4 are illustrated,but other numbers may be used.

Next, a structure of a memory cell MC is explained. Around thesemiconductor layer SC, a gate insulating layer, an insulating layer(charge storage layer), and an insulating layer (blocking layer) that isformed from a material having a higher dielectric constant than the gateinsulating layer are sequentially formed along the plane of the firstdirection and the second direction from the surface of the semiconductorlayer SC. Next, at a region where the semiconductor layer SC is formed,and in the plane of the first direction and the second direction, theword lines WL that are formed along the first direction are formed in aplurality of layers extending in the third direction. That is, at anintersection region of a word line WL and the semiconductor layer SC, amemory cell MC is formed.

An enlarged cross-sectional view of a memory cell MC along an A-A′cross-sectional direction is illustrated in an upper left corner of FIG.2. As illustrated in the drawing, a gate oxide film 24 c, a chargestorage layer 24 b, and a blocking layer 24 a are sequentially formedfrom the surface of the semiconductor layer SC and covering the surfaceof the semiconductor layer SC. Further, a conductive layer is formed ina manner covering the surface of the blocking layer 24 a. As describedabove, the memory string MS is formed in a U-shape. Therefore, with adrain side selection signal line SGD as a reference point (the drainside selection signal line SGD being provided above the uppermost wordline WL layer), the word lines WL7, WL6, WL5 and WL4 are sequentiallyformed in layers below the drain side selection signal line SGD alongthe semiconductor layer SC11. On the other side of the joint part JP,word lines WL3, WL2, WL1, WL0 and a selection signal line SGS aresequentially formed from lower layers to upper layers along thesemiconductor layer SC12.

That is, the word lines WL that are laminated in respective layers areseparately formed between the adjacent semiconductor layers SC11 andSC12 and between the adjacent semiconductor layers SC13 and SC14 t andare commonly connected between the semiconductor layers SC12-SC13 andbetween the semiconductor layers SC11-SC14.

Further, one end of the semiconductor layer SC12 that penetrates throughthe selection signal line SGS is connected to a source line SL. One endof the adjacent semiconductor layer SC13 is also connected to the sourceline SL. That is, adjacent semiconductor layers SC12 and SC13 are joinedvia the source line SL.

Further, one end of the semiconductor layer SC11 and one end of thesemiconductor layer SC14 that penetrate through the selection signallines SGD are commonly connected via a bit line BL1. Similarly, one endof the semiconductor layer SC21 and one end of the semiconductor layerSC24 that penetrate through the selection signal lines SGD are commonlyconnected via a bit line BL2; one end of the semiconductor layer SC31and one end of the semiconductor layer SC34 are also commonly connectedvia a bit line BL3; and one end of the semiconductor layer SCm1 and oneend of the semiconductor layer SCm4 are also commonly connected via abit line BLm.

The structure of a memory strings MS formed via the semiconductor layersSC13 and SC14 is the same as the memory string MS formed via thesemiconductor layers SC11 and SC12, and therefore the explanationthereof is omitted.

Here, the case where the memory cells MC0-MC7 are formed in each memorystring MS is explained as an example. However, the number of the memorycells MC that configure a memory string MS is not limited to thisnumber. The number of the memory cells MC may also be 16 and 32, forexample. In the following, when necessary, the number of the memorycells MC may be s (where s is a natural number).

As illustrated in FIG. 2, the 1st Plane is configured by arranging thememory cells MC in a three dimensional matrix form. That is, the memorycells MC are arranged in a matrix form in a lamination direction (the3^(rd) direction in FIG. 2) and are also arranged in a matrix form in ahorizontal direction orthogonal to the lamination direction (the planecomprising the 1^(st) and 2^(nd) direction in FIG. 2). As describedabove, the plurality of the memory cells MC that are arranged in thelamination direction are connected in series to form memory strings MS.A memory block BLK is configured by an aggregate of the memory stringsMS (for example, 12 memory strings MS). A plane P refers to an aggregatein which a plurality of the blocks BLK is formed. Multiple planes P cansimultaneously have read, write, or erase operations performed on them.

The explanation about the memory string MS is continued next. A drainside selection transistor SGD (referred to as the selection transistorST1 in the following) and a source side selection transistor SGS(referred to as the selection transistor ST2 in the following) that areput in a conduction state when selection is performed are connected tothe two ends of the series connected memory cells MC. The memory stringMS is arranged with the lamination direction as a longitudinaldirection. One end of the selection transistor ST1 is connected to thebit line BL. One end of the selection transistor ST2 is connected to thesource line SL.

<Cross-Sectional View of One Block BLK>

Next, the definition of the block BLK is explained using FIG. 3. FIG. 3illustrates a cross-sectional view of the above-described memory cellarray 10, with a focus here on the bit line BL0. However, in an actualconfiguration, the bit line BL1-bit line BLm are also formed in an arraytoward the back side of the paper.

As illustrated in the drawing, for example, a plurality of memorystrings MS is electrically connected to the bit line BL0. In the presentembodiment, for example, a unit configured by 12 memory strings MS isreferred to as one block BLK.

That is, for example, a unit configured by memory strings MS0-MS11 isreferred as a block BLK. For example, in a case where a plane P0 isconfigured by the bit line BL0-bit line BLm, (m+1)×12 memory strings MSare formed per one block BLK. Further the source line SL is commonlyconnected between adjacent memory strings MS in the second direction.

<Equivalent Circuit of Block BLK>

Next, a circuit diagram of the above-described memory string MS isexplained using FIG. 4. The memory strings MS0-MS11 have the sameconfiguration. Therefore, in the following, the explanation is givenwith a focus on the memory string MS0. Further, the number of the memorycells MC provided in each of the memory strings MS is 8 (s=8).

<Memory String MS0>

A circuit configuration of the memory string MS0 is explained next. Thememory string MS0 is provided with the memory cell MC0-MC7, theselection transistor ST1 and the selection transistor ST2, as well as atransistor ST_BG.

Control gates CG of the memory cells MC0-MC7 also function as word linesWL.

That is, 8 word lines WL penetrate through the memory string MS0.

The memory cells MC0-MC3 are connected in series between the selectiontransistor ST2 and the selection transistor ST_BG.

The other end of a current path of the selection transistor ST2 isconnected to the source line SL, and a signal SGS0 is supplied to a gateof the selection transistor ST2. Further, one end of a current path ofthe selection transistor ST_BG is connected to one end of a current pathof the memory cell MC3 and a signal BG is supplied to a gate of theselection transistor ST_BG.

Further, the memory cells MC4-MC7 are connected in series between theselection transistor ST1 and the selection transistor ST_BG. The otherend of a current path of the selection transistor ST1 is connected tothe bit line BL0, and a signal SGD0 is supplied to a gate of theselection transistor ST1. Further, the other end of the current path ofthe selection transistor ST_BG is connected to one end of a current pathof the memory cell MC4.

As described above, the memory strings MS1-MS11 have the sameconfiguration as the memory string MS0, and therefore their explanationis omitted.

The gates of the memory cells MC0-memory cells MC7 provided in thememory string MS0-memory string MSk are commonly connected to form oneblock BLK.

Specifically, the control gates CG are commonly connected to controlgates CG that configure all memory cells MC0 in memory string MS0-memorystring MS11 that are connected to the other bit lines BL1-BLm (notillustrated in the drawing).

<Detailed Connection Example of Memory Cell Array 10 and PeripheralCircuit 20>

Next, a detailed connection example of the above-described memory cellarray 10 and peripheral circuit 20 is explained using FIG. 5-FIG. 9. Asillustrated in FIG. 5, the peripheral circuit 20 is provided with aswitch circuit 30. In addition to the switch circuit 30, the peripheralcircuit 20 is also provided with a voltage generating circuit, a senseamplifier, a driver circuit, a control part, and the like. Here, theexplanation is given with a focus on the switch circuit 30.

Further, as an example, separate memory blocks are grouped in units oftwo to form a single memory block. That is, here block BLK0 and blockBLK1 are grouped to form a single memory block BLK; block BLK2 and blockBLK3 likewise form a single block BLK; and block BLK(i−2) and blockBLK(i−1) are grouped to form one block BLK. In other words, it isassumed that every two blocks are grouped into a single memory blockhaving two sub-blocks.

One block decoder BD is arranged for each of the group of the block BLK0and the block BLK1, the group of the block BLK2 and the block BLK3; . .. , and the group of the block BLK(i−2) and the block BLK(i−1).

Thus, when i=1000, 500 block decoders BD are arranged. Further, backgate elements BG that configure the memory strings MS, and the like, areomitted. However, when every two blocks BLK are shared, selection andnon-selection of the back gate element BG are controlled by two-blockunits.

The concept of a connection relation of the switch circuit 30 accordingto the present embodiment, the above-described memory cell array 10, andthe Xfer_S and Xfer_D, is as follows.

Specifically, 24 signal lines SGS0-SGS23, 24 signal lines SGD0-SGD23 and16 word lines WL0-WL15 that are connected via Xfer_S and Xfer_D from theBLK0-BLK(i−1) in the memory cell array 10 are connected to the switchcircuit 30.

That is, the signal line SGS0, the signal line SGD0, . . . , the signalline SGS11, and the signal line SGD11 that are drawn from the blockBLK0, the block BLK2, . . . , and the block BLK(i−2) are mutually joinedvia transfer transistors Tr_(SGD_0)-Tr_(SGD_11) and transfer transistorsTr_(SGS_0)-Tr_(SGS_11), and these groups of the signal lines SGS and thesignal lines SGD are connected to the switch circuit 30 (here i=2k,where k is a positive integer). Further, signals BLKSEL and BLKSELn arerespectively supplied to gates of the transfer transistorsTr_(SGD_0)-Tr_(SGD_11) and the transfer transistorsTr_(SGS_0)-Tr_(SGS_11).

The signal line SGS12, the signal line SGD12, . . . , and the signalline SGS23 that are drawn from the block BLK1, the block BLK3, . . . ,and the BLK(i−1) are mutually joined via the transfer transistorsTr_(SGD_0)-Tr_(SGD_11) and the transfer transistorsTr_(SGS_0)-Tr_(SGS_11), and these groups of the signal lines SGS and thesignal lines SGD are connected to the switch circuit 30. Further, thesignals BLKSEL and BLKSELn are respectively supplied to gates of thetransfer

-   transistors Tr_(SGD_0)-Tr_(SGD_11) and the transfer transistors    Tr_(SGS_0)-Tr_(SGS_11).

The word line WL0-the word line WL7 that are drawn from the block BLK0,the block BLK2, . . . , the BLK(i−2) are joined between the memorystrings MS in each block BLK, and thereafter, after passing through thetransfer transistors Tr_(MC_0)-Tr_(MC_7), are mutually joined, and theseword lines WL0-WL7 are connected to the switch circuit 30. Further, thesignal BLKSEL is supplied to gates of the transfer transistorsTr_(MC_0)-Tr_(MC_7).

Further, the word line WL8-the word line WL15 that are drawn from theblock BLK1, the block BLK3, . . . , and the block BLK(i−1) are alsojoined in the same way (that is, they are mutually joined after passingthrough the transfer transistors Tr_(MC_8)-Tr_(MC_15)), and these wordlines WL are connected to the switch circuit 30. Further, the signalBLKSEL is also supplied to gates of the transfer transistorsTr_(MC_8)-Tr_(MC_15).

In the following a specific connection relation is explained.

<Connection Relation of Block BLK0 and Corresponding Xfer_S and Xfer_D>

First, with a focus on the Sub-BLK0, the signal line SGD, the signalline SGS and a signal line CG are explained.

<Signal Line SGD and Signal Line SGS>

<Sub-BLK0>

A signal line SGD_0 connected to a gate of the selection transistor ST1is connected to one end of a current path of a MOS transistor Tr_(SGD_0)at a node N0. Further, the signal line SGD_0 is connected to a node N0′via the other end of the MOS transistor Tr_(SGD_0).

Further, a signal line SGS_0 connected to a gate of the selectiontransistor ST2 is connected to one end of a current path of a MOStransistor Tr_(SGS_0) at a node N1. Further, the signal line SGS_0 isconnected to a node N1′ via the other end of the MOS transistorTr_(SGS_0).

The same applies to signal lines SGD_1-SGD_11 and signal linesSGS_1-SGS_11. That is, the signal lines SGD_1-SGD_11 and the signallines SGS_1-SGS_11 are also connected to the switch circuit 30 viacorresponding MOS transistors Tr_(SGD) and Tr_(SGS).

<Sub-BLK1-Sub-BLK11>

In the above, the explanation is given with a focus on the Sub-BLK0.However, the same applies to the other Sub-BLK1-Sub-BLK11. That is, theselection lines (SGS_0 to SGS_11 and SGD_0 to SGD_11) that are drawnfrom the Sub-BLK1-the Sub-BLK11 are also connected to the switch circuit30 via corresponding MOS transistors Tr_(SGD) and Tr_(SGS).

<Word Line WL>

<Sub-BLK0>

The word line WL0 connected to the memory cell MC0 is connected to oneend (node N20) of a current path of the MOS transistor Tr_(MC0).Further, the word line WL0 is connected to a node N20′ via the other endof the current path of the MOS transistor Tr_(MC0).

<Sub-BLK1>

The word line WL0 drawn from the Sub-BLK1 also is connected to the nodeN20 and to the node N20′ via the MOS transistor Tr_(MC0).

Here, the explanation is given with a focus on the word lines WL0 of theSub-BLK0 and the Sub-BLK1. However, the same applies to the word linesWL0 drawn from the Sub-BLK2-the Sub-BLK11.

Further, the same applies to the word line WL1-the word line WL7 thatare respectively drawn from each of the Sub-BLK0-the Sub-BLK11. Forexample, the word lines WL7 that are respectively drawn from theSub-BLK0-the Sub-BLK11 are commonly connected at a node N22 and areconnected to a node N22′ via the corresponding MOS transistor Tr_(MC7).

In this way, the word line WL1-the word line WL7 are also commonlyconnected between the Sub-BLK0-the Sub-BLK11, and then are connected tothe switch circuit 30 via the corresponding MOS transistor Tr_(MC1)-MOStransistor Tr_(MC7).

<Connection Relation of BLK0, BLK2, . . . , and BLK(i−2)>

<Signal Line SGD and Signal Line SGS>

First, the signal line SGD and the signal line SGS are explained. Forexample, the signal line SGD_0 that is drawn from the Sub-BLK0 in theblock BLK0 and the signal lines SGD_0 that are each respectively drawnfrom the Sub-BLK0 in each of the blocks BLK2, BLK4, . . . , BLK(i−2) arecommonly connected at a node N0′.

Similarly, for example, the signal line SGS_0 that is drawn from theSub-BLK0 in the block BLK0 and the signal lines SGS_0 that are eachrespectively drawn from the Sub-BLK0 in each of the blocks BLK2, BLK4, .. . , BLK(i−2) are commonly connected at a node N1′. Similarly, thesignal line SGD_11 that is drawn from the Sub-BLK11 in the block BLK0and the signal lines SGD_11 that are each respectively drawn from theSub-BLK11 in each of the blocks BLK2, BLK4, . . . , BLK(i−2) arecommonly connected at a node N4′, and the signal line SGD_11 that isdrawn from the Sub-BLK11 in the block BLK0 and the signal lines SGD_11that are each respectively drawn from the Sub-BLK11 in each of theblocks BLK2, BLK4, . . . , BLK(i−2) are commonly connected at a nodeN5′.

That is, a total of 12 signal lines SGD and 12 signal lines SGS that arecommonly connected between the blocks BLK0, BLK2, . . . , BLK(i−2) areconnected to the switch circuit 30.

<Word Line WL>

Next, the word line WL is explained. For example, the word line WL0 thatis drawn from the Sub-BLK0-Sub-BLK11 in the block BLK0 and the wordlines WL0 that are each respectively drawn from the Sub-BLK0-Sub-BLK11in each of the blocks BLK2, BLK4, BLK(i−2) are commonly connected at thenode N20′.

The same applies to the word lines WL1-WL7. That is, the word linesWL1-WL7 that are each respectively drawn from the Sub-BLK0-Sub-BLK11 inthe block BLK0 and the word lines WL1-WL7 that are each respectivelydrawn from the Sub-BLK0-Sub-BLK11 in each of the blocks BLK2, BLK4, . .. , BLK(i−2) are respectively commonly connected.

For example, as illustrated in FIG. 5, the word line WL7 that is drawnfrom the Sub-BLK0-Sub-BLK11 in the block BLK0 and the word lines WL7that are each respectively drawn from the Sub-BLK0-Sub-BLK11 in each ofthe blocks BLK2, BLK4, . . . , BLK(i−2) are commonly connected at a nodeN21′.

That is, a total of 8 word lines WL0-WL7 that are drawn from the blockBLK0, block BLK2, block BLK4, . . . , block BLK(i−2) and mutually joinedare connected to the switch circuit 30.

<Connection Relation of Block BLK1 and Corresponding Xfer_S and Xfer_D>

Next, with a focus on the Sub-BLK0 in the block BLK1, the signal lineSGD, the signal line SGS, and the signal line CG are explained.

<Signal Line SGD and Signal Line SGS>

<Sub-BLK0>

A signal line SGD_0 (also referred to as the signal line SGD_12 in thefollowing) that is connected to the gate of the selection transistor ST1is connected to one end of a current path of a MOS transistor Tr_(SGD_0)(also referred to as the MOS transistor Tr_(SGD_12) in the following) ata node N6. Further, this signal line SGD_12 is connected to a node N6′via the other end of the MOS transistor Tr_(SGD_12). Next, a signal lineSGS_0 (also referred to as the signal line SGS_12 in the following) thatis connected to the gate of the selection transistor ST2 is connected toone end of a current path of a MOS transistor Tr_(SGS_0) (also referredto as the MOS transistor Tr_(SGS_12) in the following) at a node N7.Further, the signal line SGD0 is connected to a node NT via the otherend of the MOS transistor Tr_(SGS_12).

The same applies to signal lines SGD13-SGD23 and signal linesSGS13-SGS23 in the other sub-blocks (e.g., sub-BLK1-sub-BLK 11). Thatis, the signal lines SGD13-SGD23 and the signal lines SGS13-SGS23 arealso connected to the switch circuit 30 via corresponding MOStransistors Tr_(SGD) and Tr_(SGS).

<Sub-BLK1-Sub-BLK11>

In the above, the explanation is given with a focus on the Sub-BLK0 inthe block BLK1. However, the same applies to the Sub-BLK1-Sub-BLK11 inthe block BLK1. That is, the signal lines SGD13-SGD23 and the signallines SGS13-SGS23 that are drawn from the Sub-BLK1-Sub-BLK11 are alsoconnected to the switch circuit 30 via corresponding MOS transistorsTr_(SGD) and Tr_(SGS).

<Word Line WL>

<Sub-BLK0>

A word line WL0 (also referred to as the word line WL8 in the following)that is connected to the memory cell MC0 is connected to one end (nodeN23) of a current path of a MOS transistor Tr_(MC0) (also referred to asthe MOS transistor Tr_(MC12) in the following). Further, the word lineWL8 is connected to a node N23′ via the other end of the current path ofthe MOS transistor Tr_(MC12).

<Sub-BLK1>

A word line WL0 (also referred to as the word line WL8 in the following)drawn from the Sub-BLK1 also is connected to the node N23 and to thenode N23′ via the MOS transistor Tr_(MC8).

Here, the explanation is given with a focus on the word lines WL8 of theSub-BLK0 and the Sub-BLK1. However, the same applies to the word linesWL8 drawn from the Sub-BLK2-the Sub-BLK11.

Further, the same applies to the word lines WL8-the word line WL15 thatare respectively drawn from each of the Sub-BLK0-the Sub-BLK11. Forexample, the word lines WL15 that are respectively drawn from theSub-BLK0-the Sub-BLK11 are commonly connected at a node N25 and areconnected to a node N25′ via the MOS transistor Tr_(MC15).

In this way, the word line WL8-the word line WL15 are also commonlyconnected between the Sub-BLK0-the Sub-BLK11, and then are connected tothe switch circuit 30 via the corresponding MOS transistor Tr_(MC8)-MOStransistor Tr_(MC15).

<Connection Relation of BLK1, BLK3, BLK(i−1)>

<Signal Line SGD and Signal Line SGS>

First, the signal line SGD and the signal line SGS are explained. Forexample, the signal line SGD_0 that is drawn from the Sub-BLK0 in theblock BLK1 and the signal lines SGD_0 that are each respectively drawnfrom the Sub-BLK0 in each of the blocks BLK3, BLK5, . . . , BLK(i−1) arecommonly connected at a node N6′.

Similarly, for example, the signal line SGS_0 that is drawn from theSub-BLK0 in the block BLK1 and the signal lines SGS_0 that are eachrespectively drawn from the Sub-BLK0 in each of the blocks BLK3, BLK5, .. . , BLK(i−1) are commonly connected at a node NT.

Similarly, a signal line SGD_11 (also referred to as the signal lineSGD_23 in the following) that is drawn from the Sub-BLK0 in the blockBLK1 and signal lines SGD_23 that are each respectively drawn from theSub-BLK11 in each of the block BLK3, BLK5, . . . , BLK(i−1) are commonlyconnected at a node N10′. A signal line SGS_11 (also referred to as thesignal line SGS_23 in the following) that is drawn from the Sub-BLK0 inthe block BLK1 and a signal line SGS_11 (also referred to as the signalline SGS_23 in the following) that is drawn from the Sub-BLK11 in eachof the block BLK3, BLK5, . . . , BLK(i−1) are commonly connected at anode N11′.

That is, a total of 12 signal lines SGD and 12 signal lines SGS that arecommonly connected between the blocks BLK1, BLK3, BLK5, . . . , BLK(i−1)are connected to the switch circuit 30.

As described above, a total of 24 signal lines SGD and 24 signal linesSGS, including 12 signal lines SGD and 12 signal lines SGS that arecommonly connected between the BLK0, BLK2, . . . , BLK(i−2) and 12signal lines SGD and 12 signal lines SGS that are commonly connectedbetween the BLK1, BLK3, BLK5, . . . , BLK(i−1), are connected to theswitch circuit 30.

<Word Line WL>

Next, the word line WL is explained. For example, the word line WL8 thatis drawn from the Sub-BLK0-Sub-BLK11 in the block BLK1 and the wordlines WL8 that are each respectively drawn from the Sub-BLK0-Sub-BLK11in each of the blocks BLK2, BLK4, . . . , BLK(i−2) are commonlyconnected at the node N23′.

The same applies to word lines WL9-WL15. That is, the word linesWL9-WL15 that are each respectively drawn from the Sub-BLK0-Sub-BLK11 inthe block BLK1 and the word lines WL9-WL15 that are each respectivelydrawn from the Sub-BLK0-Sub-BLK11 in each of the blocks BLK2, BLK4, . .. , BLK(i−2) are respectively commonly connected. For example, asillustrated in FIG. 5, the word line WL15 that is drawn from theSub-BLK0-Sub-BLK11 in the block BLK0 and the word lines WL15 that areeach respectively drawn from the Sub-BLK0-Sub-BLK11 in each of theblocks BLK2, BLK4, . . . , BLK(i−2) are commonly connected at a nodeN25′.

That is, a total of 8 word lines WL8-WL15 that are drawn from the blockBLK1, block BLK3, block BLK5, . . . , block BLK(i−1) and mutually joinedare connected to the switch circuit 30.

<Non-Selection MOS Transistor Tr>

In the following, a non-selection MOS transistor Tr in the Xfer_S andthe Xfer_D corresponding to the block BLK0 and the block BLK1 isexplained. In FIG. 5, the Xfer_S and the Xfer_D are collectivelyillustrated. However, in practice, as illustrated in FIG. 1, the Xfer_Sand the Xfer_D are arranged at two ends of the MAT11 in a mannersandwiching the MAT11.

When a corresponding memory string MS is not selected, the non-selectionMOS transistor Tr in the Xfer_S and the Xfer_D is put in an ON state bythe control of the block decoder BD; that is, the non-selection MOStransistor Tr in the Xfer_S and the Xfer_D has a function oftransferring a ground potential to the selection transistors ST1 andST2. The same applies to the non-selection MOS transistors Tr in theXfer_S and the Xfer_D that correspond to each of the block BLK2 andblock BLK3, . . . , and the block BLK(i−2) and block BLK(i−1), andtherefore, the explanation of these non-selection MOS transistors Tr isomitted.

In the Xfer_S and the Xfer_D that correspond to the block BLK0 and blockBLK1, a MOS transistor Tr group is provided in which a signal BLKSELnthat the block decoder BD outputs is supplied to gates of the MOStransistor Tr group and a non-selection potential is supplied to oneends of current paths of the MOS transistor Tr group.

In the following, the connection relation is specifically explained. Oneend of a current path of a MOS transistor Tr_(SGDU_0) is supplied with anon-selection potential (VSS_1) and the other of the current path of theMOS transistor Tr_(SGDU_0) is commonly connected with the signal lineSGD_0 at the node N0. Further, one end of a current path of a MOStransistor Tr_(SGSU_0) is supplied with a non-selection potential(VSS_2) and the other of the current path of the MOS transistorTr_(SGSU_0) is commonly connected with the signal line SGS_0 at the nodeN1.

Further, one end of a current path of a MOS transistor Tr_(SGDU_1) issupplied with the non-selection potential (VSS_1) and the other of thecurrent path of the MOS transistor Tr_(SGDU_1) is commonly connectedwith the signal line SGD_1 at the node N2, and one end of a current pathof a MOS transistor Tr_(SGSU_1) is supplied with the non-selectionpotential (VSS_2) and the other of the current path of the MOStransistor Tr_(SGSU_1) is commonly connected with the signal line SGS_1at the node N3.

Similarly, the same applies to MOS transistor Tr_(SGDU_2)-MOS transistorTr_(SGDU_23), and MOS transistor Tr_(SGSU_2)-MOS transistorTr_(SGSU_23).

That is, for example, one end of a current path of the MOS transistorTr_(SGDU_23) is supplied with the non-selection potential (VSS_1) andthe other of the current path of the MOS transistor Tr_(SGDU_23) iscommonly connected with the signal line SGD_23 at the node N10, and oneend of a current path of a MOS transistor Tr_(SGSU_23) is supplied withthe non-selection potential (VSS_2) and the other of the current path ofthe MOS transistor Tr_(SGSU_23) is commonly connected with the signalline SGS_23 at the node N11.

In practice, the other ends of the current paths of the MOS transistorTr_(SGDU_6)-MOS transistor Tr_(SGDU_11), MOS transistor Tr_(SGSU_6)-MOStransistor Tr_(SGSU_11), MOS transistor Tr_(SGDU_18)-MOS transistorTr_(SGDU_23), and MOS transistor Tr_(SGSU_18)-MOS transistorTr_(SGSU_23) are supplied with a potential (which is also anon-selection potential) that is different from the above-explainednon-selection potentials (e.g., not a ground potential).

<Block Decoder BD>

Next, the block decoder BD is explained. As described above, a blockdecoder BD is provided for every two blocks BLK (for example, the groupof block BLK0 and block BLK1, the group of block BLK(i−2) and blockBLK(i−1)). That is, for i blocks BLK, there exist block decoderBD_1-block decoder BD_(i−1)/2.

These block decoders BD select or unselect the blocks BLK. Specifically,when the signal BLKSEL that the block decoders output is set at a “H”level (e.g., a high level), the MOS transistors Tr_(SGD_0)-Tr_(SGD_23),the MOS transistors Tr_(SGS_0)-Tr_(SGS_23) and the MOS transistorsTr_(MC0)-Tr_(MC95) are put in the ON state and the corresponding blocksBLK are selected.

On the other hand, when the signal BLKSELn that the block decodersoutput is put at the “H” level, the MOS transistorsTr_(SGDU_0)-Tr_(SGDU_23) and the MOS transistor Tr_(SGSU_0)-Tr_(SGSU_23)are put in the ON state, and the corresponding blocks BLK are put in anon-selection (unselected) state.

That is, among the blocks BLK of the block BLK0-block BLK(i−1), thesignal BLKSEL that is output by the block decoders BD corresponding tothe blocks BLK in a selection state is put at the “H” level. The otherblock decoders BD output the signal BLKSELn at the “H” level.

<Structure of Block Decoder BD>

Next, the structure of a block decoder BD and equivalent circuit areexplained using FIG. 6 and FIG. 7. FIG. 6 illustrates a block diagram ofa block decoder BD. FIG. 7 illustrates an equivalent circuit of theblock decoder BD.

The block decoder BD is explained using FIG. 6. Here, a case where 4blocks BLK are shared is explained as an example. That is, for example,the block BLK0, block BLK1, block BLK2 and block BLK3 are in oneaggregate, and one block decoder BD is provided for these four blocksBLK.

As illustrated in FIG. 6, the block decoder BD is provided with a latchcircuit LAT1, an address decoder unit 41, a MOS transistor 42, a levelshifter 43, and a level shifter 44.

<Latch Circuit LAT1>

The latch circuit LAT1 holds data that indicates whether a correspondingblock BLK (for example, BLK0-BLK3) is defective. Specifically, when thecorresponding block BLK is defective, the latch circuit LAT1 holds a “L”level (e.g., a low level). On the other hand, when the correspondingblock BLK is non-defective, the latch circuit LAT1 holds the “H” level.Here, for example, when the block BLK2 is defective, the latch circuitLAT1 holds the “L” level. When all corresponding blocks BLK areconsidered as defective, the latch circuit LAT1 holds the “L” level, andon the other hand, when any one block BLK among the corresponding blocksBLK is considered as non-defective and other remaining blocks BLK areconsidered as defective, the latch circuit LAT1 can stop the latchfunction.

<Address Decoder 41>

Next, the address decoder 41 is explained. A plurality of addresssignals (indicated as “address signal” in the drawing) are input to theaddress decoder 41. As described above, the block decoder BD is providedfor a unit of four blocks BLK. The address signal includes the number ofbits necessary for selecting, for example, each of the four blocks BLKof an aggregate unit of all the blocks BLK.

For example, when a signal address indicating the block BLK0 is input,the block decoder BD outputs the signal BLKSEL=“H” level and the signalBLKSELn=“L” level.

On the other hand, for example, when any of the block BLK0-block BLK3 isnot selected, the block decoder BD outputs the signal BLKSEL=“L” leveland the signal BLKSELn=“H” level.

<Level Shifters LS43 and LS44>

The level shifter LS43 outputs the signal BLKSELn based on an inputsignal that is inverted by an inverter inv1, and the level shifter LS44outputs the signal BLKSEL based on the input signal. These levelshifters LS43 and LS44 boost, for example, an input voltage VDD up to awrite voltage or a read voltage. Therefore, the signal BLKSEL and thesignal BLKSELn are generally high voltage signals.

<Equivalent Circuit of Block Decoder BD>

Next, an equivalent circuit of the above-described block decoder BD isexplained using FIG. 7.

<Latch Circuit LAT1>

The latch circuit LAT1 is explained next. In the following, whennecessary, the latch circuit LAT1 may be explained as corresponding tothe block BLK0-block BLK3. The latch circuit LAT1 is provided withn-channel MOS transistors 60-63, p-channel MOS transistors 64 and 65, aninverter inv10, and an inverter inv11.

One end of a current path of the MOS transistor 60 is connected to anode N40, and a node N42 is connected to a gate of the MOS transistor60. One end of a current path of the MOS transistor 61 is connected tothe other end of the current path of the MOS transistor 60; a signal RSTis supplied to a gate of the MOS transistor 61; and the other end of thecurrent path of the MOS transistor 61 is grounded. That is, when the MOStransistors 60 and 61 are put in an ON state, the node N40 is put at the“L” level.

One end of a current path of the MOS transistor 62 is connected to anode N41; the other end of the current path of the MOS transistor 62 isconnected to one end of a current path of the MOS transistor 63; and asignal SET is supplied to a gate of the MOS transistor 62. Further, theother end of the current path of the MOS transistor 63 is grounded, anda gate of the MOS transistor 63 is connected to the node N42. That is,when the MOS transistor 62 and the MOS transistor 63 are all put in theON state, the node N41 is put at the “L” level.

The voltage VDD is supplied to one end of a current path of the MOStransistor 64; the signal RST is supplied to a gate of the MOStransistor 64; and the other end of the current path of the MOStransistor 64 is connected to the node N40. Further, the voltage VDD issupplied to one end of a current path of the MOS transistor 65; thesignal SET is supplied to a gate of the MOS transistor 65; and the otherend of the current path of the MOS transistor 65 is connected to thenode N41.

Next, the inverters inv10 and inv11 are explained. A holding part isconfigured by the inverters inv10 and inv11. That is, an output terminalof the inverter inv10 is connected to an input terminal of the inverterinv11, and an output terminal of the inverter inv11 is connected to aninput terminal of the inverter inv10.

In the following, a signal that is input to the latch circuit LAT1 whenthe corresponding block BLK0-block BLK3 are all defective and a signalthat is input to the latch circuit LAT1 when some of the blocks BLK aredetermined to be defective (the rest of the blocks BLK are determined tobe non-defective) are explained. First, MOS transistors 74 and 75 areexplained.

When all blocks BLK are selection targets, a gate signal ON that issupplied the MOS transistor 74 is activated (in this case, the MOStransistors 70-73 are also in the ON state).

Further, when a defective block BLK becomes a target, a gate signal BBthat is supplied to the MOS transistor 75 is temporarily activated at astage before the block BLK becomes a selection target. However, whilethe block BLK is selected, the gate signal BB is fixed at a low voltageand the MOS transistor 75 is put in an OFF state.

<When all Block BLK0-Block BLK3 are Considered as Defective>

In this case, the signal SET=“H” level and the signal RST=“L” level areinput. As a result, the potential level of the node N41 transitions tothe “L” level.

Therefore, even in the case where MOS transistor 70-MOS transistor 74(to be described later) are all erroneously put in the ON state despitebeing defective block BLK targets, since a MOS transistor 66 is put inthe OFF state, a node N46 does not transition to the “L” level.

That is, the signal BLKSELn is put at the “H” level and thenon-selection potential is supplied to the block BLK0-block BLK3. Inother words, the block BLK0-block BLK3 are not selected.

<When Blocks BLK are Divided into Defective Blocks BLK and Non-DefectiveBlocks BLK>

On the other hand, when some of the block BLK0-block BLK3 arenon-defective, and the blocks BLK are divided into defective blocks BLKand non-defective blocks BLK, the latch circuit LAT1 is not operated.That is, an initial state when the nonvolatile semiconductor memorydevice is powered up is maintained. Specifically, the signal RST=“H”level and the signal SET=“L” level are input. This allows the node N41to transition to the “H” level and then, as described above, this allowsthe MOS transistor 70-MOS transistor 74 to be put in the ON state.

As will be described later, a write voltage, a read voltage, and thelike are transferred to selection blocks among the shared blocks BLK bya switch circuit 30. A write voltage, a read voltage, and the like arenot transferred to defective blocks BLK and non-selection blocks BLK.

<Address Decoder 41>

Next, the address decoder part 41 is explained. The address decoder part41 is provided with n-channel MOS transistors 70-75 and p-channel MOStransistors 78 and 79. The MOS transistors 70-75 are mutually connectedat their drains and sources in a manner to be connected in series.

The above-described signal address is supplied to gates of the MOStransistor 70-73. When any one of the block BLK0-BLK3 is selected, allof the MOS transistors 70-73 are put in the ON state by the signaladdress.

Next, when the signal ON=“H” level and the above-described MOStransistor 66 is put in the ON state, the node N46 transitions to the“L” level. Therefore, an “H” level signal as the signal BLKSEL is outputfrom the inverter inv23.

On the other hand, when all of the block BLK0-block BLK3 are in thenon-selection state, the signal ON is put at the “L” level and thepotential of the node N46 is put at the “H” level. Therefore, an “H”level signal BLKSELn is output via the inverters inv20 and inv21.

<Inverters Inv20, Inv21 and Inv22>

The node N46 is connected to an input terminal of the inverter inv20.The inverter inv20 outputs a result obtained by inverting the potentiallevel of the node N46 to the node N42 (an input terminal of the inverterinv21).

The inverter inv21 receives the potential level of the node N42 andoutputs as the signal BLKSELn a result obtained by inverting thispotential level to the block decoder BD.

Further, the inverter inv22 inverts the potential level of the node N42and outputs the result of the inversion to the inverter 23. Uponreceiving the input from the inverter 22, the inverter 23 inverts thevoltage level supplied from the inverter 22 and outputs the result ofthe inversion as the signal BLKSEL.

<Switch Circuit 30>

Next, the switch circuit 30 is explained using FIG. 8 and FIG. 9. Theswitch circuit 30 is configured primarily from a voltage switch part 31and a decoder part 32.

<Voltage Switch Part 31>

The voltage switch part 31 is provided with first switch parts throughfourth switch parts. In the present example, only one of each set of theswitch parts is illustrated and all others are omitted. However, of thefirst switch parts through the fourth switch parts, for each set of thefirst switch parts and the second switch parts, 12 switch parts areoriginally provided for selecting one block BLK (12 memory strings MS)(in the drawing, the wiring that connects the switch part and thedecoder part is indicated with a label “12”). Here, the “t-th” (t: 0-11)first switch part and the “t-th” (t: 0-11) second switch part areillustrated.

Further, 8 third switch parts are provided for applying voltage to the 8word lines WL that form one memory string MS (in the drawing, the wiringthat connects the switch part and the decoder part is indicated with alabel “8”). The third switch parts also have the same structures.Therefore, only one switch part is illustrated. Here, the “1-th” (l:0-7) third switch part is illustrated.

Further, since it is sufficient to select one block BLK among i blocksBLK that are provided, only one fourth switch part is provided.

<First Switch Part>

The first switch part is provided with n-channel MOS transistor 31-1 andMOS transistor 31-2. A voltage V2 _(S) (for example, voltage VDD) issupplied to one end of a current path of the MOS transistor 31-1; asignal St1 (t: 0-11) is supplied to a gate of the MOS transistor 31-1;and the other end of the current path of the MOS transistor 31-1 isconnected to a node N50.

When the signal St1 is put in the “H” level, the voltage V2 _(S) issupplied to one of the signal line SGS_0-signal line SGS_11 or thesignal line SGS_12-signal line SGS_23. In other words, the selectiontransistor ST2 of the corresponding memory string MS is put in theselection state.

Further, a voltage V3 _(S) is supplied to one end of a current path ofthe MOS transistor 31-2; a signal /St1 (where “/” indicates inversion;that is, the signal /St1 is an inverted signal of the signal St1) issupplied to a gate of the MOS transistor 31-2; and the other end of thecurrent path of the MOS transistor 31-2 is connected to the node N50.

That is, when the signal /St1 is put in the “H” level, the voltage V3_(S) is supplied to one of the signal line SGS_0-signal line SGS_11 orthe signal line SGS_12-signal line SGS_23. In other words, thecorresponding memory string MS is not selected.

<Second Switch Part>

Next, the second switch part is explained. It is necessary to select ornot-select a predetermined memory string MS. Therefore, a signal lineSGD that forms a pair with the above signal line SGS that is selected bythe first switch part is selected by the second switch part. The sameapplies to the memory string MS that is put as not-selected.

The second switch part is provided with n-channel MOS transistors 31-3and 31-4. A voltage V2 _(D) is supplied to one end of a current path ofthe MOS transistor 31-3; a signal Dt1 is supplied to a gate of the MOStransistor 31-3; and the other end of the current path of the MOStransistor 31-3 is connected to a node N51.

When the signal Dt1 is put in the “H” level, the voltage V2 _(D) issupplied to one of the signal line SGD_0-signal line SGD_11 or thesignal line SGD_12-signal line SGD_23. In other words, the selectiontransistor ST1 of the corresponding memory string MS is put in theselection state.

Further, a voltage V3 _(D) is supplied to one end of a current path ofthe MOS transistor 31-4; a signal /Dt1 is supplied to a gate of the MOStransistor 31-4; and the other end of the current path of the MOStransistor 31-4 is connected to the node N51.

That is, when the signal /Dt1 is put in the “H” level, the voltage V3_(D) is supplied to one of the signal line SGD_0-signal line SGD_11 orthe signal line SGD_12-signal line SGD_23. In other words, thecorresponding memory string MS is not selected.

<Third Switch Part>

The third switch parts are provided in number corresponding to thenumber of the word lines WL0-WL7 as described above. However, only oneof the third switch parts is illustrated here.

As illustrated in the drawing, the third switch part is provided with ann-channel MOS transistor 31-5. A voltage V2 c (for example, a writeoperation voltage, a read operation voltage, an erase operation voltage)is supplied to one end of a current path of the MOS transistor 31-5; asignal C1 is supplied to a gate of the MOS transistor 31-5; and theother end of the current path of the MOS transistor 31-5 is connected toa node N52.

This allows, for example, in the case of a write operation, a writeoperation voltage that is supplied from the MOS transistor 31-5 to besupplied to the word lines WL in any one memory string MS in any oneblock BLK. The same applies to the case of a read operation voltage andthe case of an erase operation voltage.

<Fourth Switch Part>

Next, the fourth switch part is explained. As described above, withrespect to the first-third switch parts, only one fourth switch part isprovided.

As illustrated in the drawing, the fourth switch part is provided withan n-channel MOS transistor 31-6. A voltage V2 _(B) (for example, apotential that puts the transistor ST_BG in the ON state, such as awrite operation non-selection voltage and a read operation non-selectionpotential) is supplied to one end of a current path of the MOStransistor 31-6; a signal B is supplied to a gate of the MOS transistor31-6; and the other end of the current path of the MOS transistor 31-6is connected to a node N53.

This allows, for example, in the case of a write operation, the writeoperation non-selection voltage V2 _(B) that is supplied from the MOStransistor 31-6 to be supplied to the gate of the selection transistorST_BG of any one block BLK. The same applies to the case of a readoperation voltage and the case of an erase operation voltage.

<Decoder Part 32>

The decoder part 32 is provided with a decoder Dec_S, a decoder Dec_D, adecoder Dec_B, and a decoder Dec_C, as depicted in FIG. 8. In thefollowing, the explanation is given assuming the case where the numberof sharing blocks is n=4. That is, the signal lines SGS (a total of 48of them) that are drawn from, for example, the block BLK0-block BLK3 areconnected to the decoder Dec_S.

Similarly, the signal lines SGD (a total of 48 of them) that are drawnfrom the block BLK0-block BLK3 are connected to the decoder Dec_D. Next,the signal lines CG (a total of 32) that are drawn from, for example,the block BLK0-block BLK3 are connected to the decoder Dec_C.

<Decoder Dec_S>

Signals IN3 _(S), IN4 _(S), t1 _(S), t2 _(S) and t3 _(S) and voltages V4_(S) and V5 _(S) are supplied to the decoder Dec_S. The decoder Dec_Sreceives the signal IN3 _(S) and the signal IN4 _(S), and then decodesthe signal IN3 _(S) and the signal IN4 _(S). Depending on the result ofthe decoding, the decoder Dec_S selects, from the 12×4 signal lines SGS,the signal lines SGS corresponding to a particular block BLK to applythe voltage from the first switch part.

The voltage V4 _(S) is supplied to a level shifter that is provided inthe decoder Dec_S. Next, signal processing operations up to a MUXcircuit 84 and MUX circuits 80-83 of FIG. 9 are explained, the MUXcircuits 80-83 are signal output destinations of the MUX circuit 84.Since a defective cell may exist among the selected four blocks BLK,operations to a block BLK that cannot be used are prohibited. However,in the nonvolatile semiconductor memory device according to the firstembodiment, the signal BLKSEL transfers data over all the SG lines, theCG lines and the BG lines of the shared blocks BLK. Therefore, it isnecessary to set the voltage of the non-selection state in the circuitof FIG. 9.

Once a potential of selection or non-selection is provided to the SGlines, the CG lines and the BG lines at the stage of the circuit of FIG.9, there will be no problem even when data transfer via the signalBLKSEL becomes possible in the Xfer_S or Xfer_D circuit which is thenext circuit of FIG. 9.

Which block BLK is access enabled or access prohibited is supplied tothe signal t2. This signal stores data in a ROM in advance and transfersthe data from the ROM. The signal t2 reaches each BLK via wiring that isindependent for each block BLK from the MUX circuit 84.

<Decoder Dec_D>

Signals IN3 _(D), IN4 _(D), t1 _(D), t2 _(D) and t3 _(D) and voltages V4_(D) and V5 _(D) are also similarly supplied to the decoder Dec_D. Thedecoder Dec_D receives the signal IN3 _(D) and the signal IN4 _(D), andthen decodes the signal IN3 _(D) and the signal IN4 _(D).

Depending on the result of the decoding, the decoder Dec_D selects, fromthe 12×4 signal lines SGD, the signal lines SGD corresponding to aparticular block BLK to apply the voltage from the second switch part.The voltage V4 _(D) is supplied to a level shifter that is provided inthe decoder Dec_D. Connection method from the MUX circuit 84 to the MUXcircuits 80-83 is the same as explained for the decoder Dec_S and thusthe explanation thereof is omitted.

<Decoder Dec_C>

Signals IN3 _(C), IN4 _(C), t1 _(C), t2 _(C) and t3 _(C) and voltages V4_(C) and V5 _(C) are also similarly supplied to the decoder Dec_C. Thedecoder Dec_C receives the signal IN3 _(C) and the signal IN4 _(C), andthen decodes the signal IN3 _(C) and the signal IN4 _(C).

Depending on the result of the decoding, the decoder Dec_C selects, fromthe 8×4 signal lines CG, the signal lines CG corresponding to aparticular block BLK to apply the voltage from the third switch part.The voltage V4 _(C) is supplied to a level shifter that is provided inthe decoder Dec_C.

<Decoder Dec_B>

Signals IN3 _(B), IN4 _(B), t1 _(B), t2 _(B) and t3 _(B) and voltages V4_(B) and V5 _(B) are also similarly supplied to the decoder Dec_B. Thedecoder Dec_B receives the signal IN3 _(B) and the signal IN4 _(B), andthen decodes the signal IN3 _(B) and the signal IN4 _(B).

Depending on the result of the decoding, the decoder Dec_B selects, fromthe i signal lines BG, the signal lines BG corresponding to a particularblock BLK to apply the voltage from the fourth switch part. The voltageV4 _(B) is supplied to a level shifter that is provided in the decoderDec_B.

Next, an equivalent circuit of the above-described decoder part 32 isexplained using FIG. 9. For the decoder part 32 explained in thefollowing, n=4; that is, the decoder part 32 is an example of aconfiguration of the case where the block BLK sharing number is 4. As anexample, the case of the decoder Dec_S is explained. That is, it will beobvious that the number of parts that configure the decoder part 32 tobe explained in the following will increase or decrease depending on thesharing number.

The decoder part 32 holds inverters inv60 and inv61, NAND circuits70-73, MUX circuits 80-84, level shifters LS90-LS93, and n-channel MOStransistors Tr100-Tr147.

The signal IN3 is supplied to an input terminal of the inverter inv60via the node N50; and an output terminal of the inverter inv60 isconnected to the node N51. The signal IN4 is supplied to an inputterminal of the inverter inv61 via the node N52; and an output terminalof the inverter inv61 is connected to the node N53.

The NAND circuit 70 NAND-operates a voltage level of the node N50 and avoltage level of the node N52, and outputs this NAND-operation result tothe MUX circuit 80.

The NAND circuit 71 NAND-operates a voltage level of the node N51 and avoltage level of the node N53, and outputs this NAND-operation result tothe MUX circuit 81.

The NAND circuit 72 NAND-operates the voltage level of the node N50 andthe voltage level of the node N52, and outputs this NAND-operationresult to the MUX circuit 82.

The NAND circuit 73 NAND-operates the voltage level of the node N51 andthe voltage level of the node N53, and outputs this NAND-operationresult to the MUX circuit 83.

According to the control signal t2 and the control signal t3, the MUXcircuit 84 outputs either a voltage V or a ground potential (0 V). Forexample, in a case where all blocks BLK are selected such as the case ofan erase operation, according to the control signal t2 and the controlsignal t3, the MUX circuit 84 selects a voltage V5 and outputs theselected voltage V to the MUX circuits 80-83.

The signal t2 is a switch signal switching which potential among aninput potential V5 and a voltage VSS (low voltage: an inverse trianglein the drawing) of the MUX circuit 84 is to be sent to the MUX circuit80-MUX circuit 83.

Further, the signal t3 is a signal determining, with respect to the MUXcircuit 80-MUX circuit 83, to which MUX circuit to apply or not to applya voltage. The number of bits also changes depending on the block BLKsharing number n.

The MUX circuit 80 selects one of the NAND operation result from theNAND circuit 70 and the voltage level from the MUX circuit 84 based onthe control signal t1. In a normal operation, the MUX circuit 80 selectsthe NAND operation result from the NAND circuit 70 according to thecontrol signal t1. In the case where all blocks BLK are selected such asthe case of an erase operation, the MUX circuit 80 selects the voltagelevel of the MUX circuit 84 according to the control signal t1. The sameapplies to the MUX circuits 81-83.

The MUX circuit 81 selects one of the NAND operation result from theNAND circuit 71 and the voltage level from the MUX circuit 84 based onthe control signal t1. The MUX circuit 82 selects one of the NANDoperation result from the NAND circuit 72 and the voltage level from theMUX circuit 84 based on the control signal t1. The MUX circuit 83selects one of the NAND operation result from the NAND circuit 73 andthe voltage level from the MUX circuit 84 based on the control signalt1.

The level shifter 90 boosts a signal supplied from the MUX circuit 80 bya voltage V1. Subsequently, the level shifter 90 supplies the boostedvoltage to gates of corresponding MOS transistor 100-MOS transistor 111(MOSTr100-111).

For example, when the signal supplied from the MUX circuit 80 is the “H”level, each of the MOS transistors 100-111 is put in the ON state, andthe voltages (such as the voltage V2 _(S) and the voltage V3 _(S))applied from the voltage switch part 31 are applied to the Xfer_S andXfer_D via these MOS transistors 100-111. In this case, the other MOStransistors 112-147 (MOSTr112-147) are put in the OFF state.

The level shifter 91 boosts a signal supplied from the MUX circuit 81 bythe voltage V1. Subsequently, the level shifter 91 supplies the boostedvoltage to gates of corresponding MOS transistor 112-MOS transistor 123(MOSTr112-123).

For example, when the signal supplied from the MUX circuit 81 is the “H”level, each of the MOS transistors 112-123 is put in the ON state, andthe voltages (such as the voltage V2 _(D) and the voltage V3 _(D))applied from the voltage switch part 31 are applied to the Xfer_S andXfer_D via these MOS transistors 112-123. In this case, the other MOStransistors 100-111 and the MOS transistors 124-147 are put in the OFFstate. The same applies to the level shifters 92 and 93 and thus theirexplanation is omitted.

<Effects According to First Embodiment>

The following effects can be obtained in a nonvolatile semiconductormemory device according to the first embodiment of the presentdisclosure. (1) The area of the peripheral circuit can be reduced. Asdescribed above, in the first embodiment, a plurality of blocks BLK areshared, and one block decoder BD is arranged for the plurality of blocksBLK. Therefore, the number of the block decoders BD provided in thenonvolatile semiconductor memory device can be reduced. For example,when the number of sharing units of the blocks BLK is n=2, the number ofthe arranged block decoders BD is reduced by half; and when the numberof sharing units is n=4, the number of the arranged block decoders BD isfurther reduced by half again.

FIGS. 10A-10C illustrate conceptual diagrams showing the reduction ofthe area. FIG. 10A illustrates the case of a nonvolatile semiconductormemory device as a comparative example where the sharing number n=1,that is, one block decoder BD is provided for each block BLK. FIG. 10Billustrates the case where the sharing number n=2 in the firstembodiment; and FIG. 10C illustrates the case where the sharing numbern=4.

As illustrated in FIG. 10A, in the case where, without sharing aplurality of blocks BLK, one block decoder BD is arranged for each blockBLK, the above-described inverters inv20-inv22 (indicated as BUF0, BUF1,. . . in FIG. 10A), latch circuits LAT (indicated as LAT0, LAT1, . . .in FIG. 10A), and address decoder parts 41 (indicated as Add0, Add1, . .. in FIG. 10A) are arranged for each block BLK. The lateral directionillustrates the width of the block BLK. On the other hand, asillustrated in FIG. 10B, when the sharing number n=2, the latch circuitLAT1, inverter inv20-inv22 and address decoder part 41 are provided fora plurality of sharing blocks BLK, and therefore the numbers of theprovided latch circuit LAT1, inverter inv20-inv22 and address decoderpart 41 are reduced according to the sharing number n. That is, asillustrated in FIG. 10B, when the sharing number n=2, the latch circuitLAT1, inverter inv20-inv22 and address decoder part 41 are provided forevery two blocks BLK. Therefore, the area occupied is about half of thatof the comparative example.

Further, as illustrated in FIG. 10C, when the sharing number n=4, thelatch circuit LAT1, inverter inv20-inv22 and address decoder part 41 areprovided for every four blocks BLK. Therefore, the area occupied isabout ¼ of that of the comparative example.

Therefore, it is clear that, as a whole, the area occupied by the blockdecoder BD reduces as the sharing number n decreases. In the firstembodiment, the optimal value of the sharing number is n=4. Newly addedcircuit parts can be accommodated under the cell array 10. Therefore,even when the circuit is enlarged, a chip area does not increase.Therefore, an effect of reducing the area of the block decoder BD can beproduced.

(2) Wirings Arranged Under the Memory Cell Array can be Reduced.

In FIG. 5, for convenience, the Xfer_D and the Xfer_S are collectivelyindicated. However, in practice, as illustrated in FIG. 1, the Xfer_Sand the Xfer_D are positioned at two ends of the memory cell array. Asdescribed above, the block decoder BD is connected to the Xfer_S and theXfer_D via wirings so as to select MOS transistor groups in the Xfer_Dand the Xfer_S. Here, the comparative example is explained. In thecomparative example, a nonvolatile semiconductor memory device isassumed in which, without sharing a plurality of blocks BLK, one blockdecoder BD is arranged for each one block BLK. That is, in order toselect the Xfer_D and the Xfer_S that are positioned at the two ends ofthe block BLK, signal wirings supplying the signal BLKSEL and the signalBLKSELn from one block decoder BD are arranged.

As can also be seen from FIG. 1, the signal wirings (two wirings of thesignal BLKSEL and the signal BLKSELn) connecting the block decoder BDand, for example, a gate of a MOS transistor in the Xfer_D pass throughdirectly under where the memory cell array 10 is formed. That is, themore there are signal wirings passing through directly under the memorycell array 10, the more the area of the circuit arranged under the cellarray is enlarged. In the case of the comparative example, the signalwirings (two wirings of the signal BLKSEL and the signal BLKSELn)connecting the block decoder BD and, for example, a gate of a MOStransistor in the Xfer_D are arranged for each block BLK.

However, in the case of the nonvolatile semiconductor memory deviceaccording to the present embodiment, as described above, the blocks BLKare shared. For example, when the sharing number n=2, the number of thearranged block decoders BD is half of that of the comparative example.That is, the number of signal wirings from the block decoder BD to, forexample, the Xfer_D is also half of that of the comparative example.

As described above, by increasing the number of sharing blocks, thenumber of wirings added directly under the memory cell array 10 isreduced. This allows the area of the circuit arranged under the cellarray to be reduced.

Based on the above description, FIG. 11 illustrates a conceptual depictshow the number of the signal wirings (signal BLKSEL and signal BLKSELn)is reduced when the number n of sharing blocks is increased. In FIG. 11,not only the numbers of the signal BLKSEL and the signal BLKSELnwirings, the numbers of the signal lines SGS, the signal lines SGD andthe signal lines CG are also mentioned. Further, the total number ofblocks arranged in the MAT11 is assumed to be 1000.

As illustrated in FIG. 11, the number of sharing blocks (the sharingnumber n), the number of memory cells MC laminated in one semiconductorlayer SC, the number of signal lines SGS, the number of signal linesSGD, the number of signal lines CG, the number of signal wirings (BLKSELand BLKSELn) are indicated; the respective numbers of the signal lineswhen the sharing number n is increased are indicated. The number of thememory cells MC laminated in one semiconductor layer SC is assumed to be24. That is, the memory string MS is configured by the memory cellMC0-memory cell MC47.

As illustrated in FIG. 11, in the case of the nonvolatile semiconductormemory device of the comparative example (in which the sharing numbern=1), as described above, one block decoder BD is arranged for eachblock BLK. Therefore, the numbers of the signal wirings (the number ofsignal lines for the signal BLKSEL and the number of signal lines forthe signal BLKSELn) are equal to the number of the blocks BLK, that is,each of the numbers is 1000. Further, in the comparative example, thesignal lines SGS, the signal lines SGD and the signal lines CG arecommonly connected at all blocks BLK. Therefore, as illustrated in FIG.11, the numbers of these signal lines are respectively, from the top,12, 12, and 48.

On the other hand, when the sharing number n=2, as described above, eachof the numbers of the signal wirings (the number of signal lines for thesignal BLKSEL and the number of signal lines for the signal BLKSELn) is500. In this case, the numbers of the signal lines SGS, the signal linesSGD and the signal lines CG that are drawn from the sharing blocks BLK(for example, the block BLK0 and the block BLK1) are respectivelydoubled as compared to the comparative example. However, when thenonvolatile semiconductor memory device is viewed as a whole, only 1168signal lines are required, which is approaching half of that of thecomparative example (2096 signal line).

Similarly, the case where the sharing number n=4 is explained. In thiscase, one block decoder BD is provided for each of the block BLK0-blockBLK3 group, the block BLK4-block BLK7 group, . . . , and the blockBLK(i−4)-block BLK(i−1) group. Therefore, each of the numbers of thesignal wirings (the number of signal lines for the signal BLKSEL and thenumber of signal lines for the signal BLKSELn) from the block decoder BDto the Xfer_D is 250. In this case, the signal lines SGS, the signallines SGD and the signal lines CG are drawn from the sharing blocks BLK(for example, the block BLK0-block BLK3). Therefore, the numbers ofthese signal lines are respectively four times of that of thecomparative example (in FIG. 11 the numbers are 48, 48, and 192, fromthe top).

However, when the nonvolatile semiconductor memory device is viewed as awhole, only 812 signal lines are required, which is about 1200 signallines less than that of the comparative example (2096 signal lines).

(3) All Blocks BLK can be Selected.

In the case of the nonvolatile semiconductor memory device according tothe first embodiment, in which the sharing number n=4, the signal linesSGS and the signal lines SGD are separately drawn from the four sharingblocks BLK. That is, 48 signal lines SGS and 48 signal lines SGD aredrawn as compared to 12 signal lines SGS and 12 signal lines SGD in thecase of the comparative example. In without additional elements to theconfiguration, the desired voltage application in the first embodimentcould only be performed on one block BLK of the four sharing blocks BLK.That is, in this case, selecting all blocks BLK would not be possible.Further, separating accessible and not-accessible blocks BLK also couldnot be performed.

This can also be seen from the configuration of the MUX circuits and theMOS transistor 100-MOS transistor 147 corresponding to the MUX circuitsin FIG. 9.

Taking this point into consideration, in the first embodiment, the MUXcircuit 84 and the control signal t2 and control signal t3 that controlthe MUX circuit 84 are further provided in FIG. 9.

As described above, the MUX circuit 84 has a function of supplying thevoltage V5 to each of the MUX circuits 80-83 according to the controlsignals t2 and t3 in the case of selecting all the blocks BLK, In thiscase, according to the control signal t1, each of the MUX circuit 80-MUXcircuit 83 selects the voltage level supplied by MUX circuit 84regardless of the outputs of the NAND circuits 70-73.

That is, in the case of selecting all the blocks BLK, the voltage V5 isoutput from the MUX circuit 80-MUX circuit 83 and all of thecorresponding MOS transistor 100-MOS transistor 147 are put in the ONstate. Therefore, selecting all the blocks BLK can be performed, andeven when the signal lines SGS and the signal lines SGD are separatelydrawn, therefore, for example, an erase operation and the like can beexecuted.

Second Embodiment

Next, a nonvolatile semiconductor memory device according to a secondembodiment is explained. The nonvolatile semiconductor memory deviceaccording to the second embodiment is different in the configuration ofthe decoder part 32. In the case of the nonvolatile semiconductor memorydevice according to the second embodiment, a voltage can be supplied toa non-selection block BLK. In the following, a configuration of adecoder part 32 according to the second embodiment is illustrated inFIG. 12. Only where the configuration is different from that of theabove FIG. 9 is explained. As an example of the decoder part 32, thecase of the above-described decoder Dec_S is explained.

<Decoder Part 32—Second Embodiment>

As illustrated in FIG. 12, the decoder part 32 according to the secondembodiment further comprises inverters inv200-203, level shiftersLS90′-LS93, n-channel MOS transistor 210-MOS transistor 258, and avoltage generating part 260. The case where the number of sharing blocksBLK is four (n=4) is explained.

An input terminal of the inverter inv200 is connected to a node N60 andan output terminal of the inverter inv200 is connected to the levelshifter LS90′. The level shifter LS90′ receives input from the inverterinv200, and, according to the input, supplies a boosted voltage to gatesof the MOS transistors 210-221. Further, one end of current paths of theMOS transistors 210-221 are respectively connected to one end of currentpaths of the corresponding MOS transistor 100-MOS transistor 111, andthe other ends of the current paths of the MOS transistors 210-221 areconnected to a node N70.

An input terminal of the inverter inv201 is connected to a node N61 andan output terminal of the inverter inv201 is connected to the levelshifter LS91′. The level shifter LS91′ receives input from the inverterinv201, and, according to the input, supplies a boosted voltage to gatesof the MOS transistors 222-233. Further, one end of current paths of theMOS transistors 222-233 are respectively connected to one end of currentpaths of the corresponding MOS transistor 112-MOS transistor 123, andthe other end of the current paths of the MOS transistors 222-233 areconnected to the node N70.

An input terminal of the inverter inv202 is connected to a node N62 andan output terminal of the inverter inv202 is connected to the levelshifter LS92′. The level shifter LS92′ receives input from the inverterinv202, and, according to the input, supplies a boosted voltage to gatesof the MOS transistors 234-245. Further, one end of current paths of theMOS transistors 234-245 are respectively connected to one end of currentpaths of the corresponding MOS transistor 124-MOS transistor 135, andthe other end of the current paths of the MOS transistors 234-245 areconnected to the node N70.

An input terminal of the inverter inv203 is connected to a node N63 andan output terminal of the inverter inv203 is connected to the levelshifter LS93′. The level shifter LS93′ receives input from the inverterinv203, and, according to the input, supplies a boosted voltage to gatesof the MOS transistors 246-257. Further, one end of current paths of theMOS transistors 246-257 are respectively connected to one end of currentpaths of the corresponding MOS transistor 136-MOS transistor 146, andthe other end of the current paths of the MOS transistors 246-257 areconnected to the node N70.

Further, when the voltage generating part 260 receives a signal F andthe MOS transistor 258 is put in an ON state, the voltage generatingpart 260 supplies a voltage V3 (for example, the voltage VDD and thevoltage VSS) to the node N70. That is, when the MOS transistors 210-257are put in the ON state by the level shifters LS90′-93′, even when aresult of decoding a signal IN5 and a signal IN6 is a non-selectionblock BLK, the voltage V3 can be supplied.

In the explanation of the decoder part 32 described above, as anexample, the case of the decoder Dec_S is explained. However, thedecoder Dec_D or the decoder Dec_C may also be similarly explained.

<Effects According to Second Embodiment>

In the case of the nonvolatile semiconductor memory device according tothe second embodiment, in addition the above-described effects (1)-(3),an effect (4) can be further obtained.

(4) An Erroneous Operation can be Inhibited.

That is, in the second embodiment, the level shifters LS90′-93′, thevoltage generating circuit 260, and the MOS transistors 210-358 arefurther provided.

Therefore, as described above, even when the MUX circuits 80-83 are putat the “L” level, one of the MOS transistors 210-257 is put in the ONstate by the output of the inverters inv200-203, and a voltage can besupplied to a non-selection block BLK. In this way, by applying acertain voltage a non-selection block BLK, an erroneous operation can beinhibited.

Third Embodiment

Next, a nonvolatile semiconductor memory device according to a thirdembodiment is explained. The third embodiment has a configuration inwhich level shifters LS are provided in the Xfer_S and the Xfer_D. Thelevel shifters LS are provided for each of the blocks BLK. The Xfer_Sand the Xfer_D have the same configuration. Therefore, in the followingembodiment, the Xfer_S is explained using a simplified block diagram.

<Simplified Diagram of Xfer_S>

As illustrated in FIG. 13, in addition to the MOS transistor groups (MOStransistors Tr_(SGD), Tr_(SGS), Tr_(MC), and the like illustrated inFIG. 5), the Xfer_S is provided the level shifters LS.

The signal BLKSEL and signal BLKSELn that are supplied from the blockdecoder BD are input to the level shifters LS. The level shifters LSchange the value of a voltage supplied from the block decoder BD from ahigh voltage to a low voltage. The level shifters LS then supply the lowvoltage to the MOS transistor groups (e.g., MOSTr 100-148).

<Effects According to Third Embodiment>

In the case of the nonvolatile semiconductor memory device according tothe third embodiment, in addition the above-described effects (1)-(4),an effects (5) and (6) can be further obtained.

(5) Power Consumption can be Reduced.

In the case of the nonvolatile semiconductor memory device according tothe third embodiment, the level shifters LS are provided in the Xfer_Sand the Xfer_D. The voltage that is applied to the gates of the MOStransistor Tr groups is lowered by the level shifters LS. Therefore, thepower consumption applied to the gates of the MOS transistor groups(MOSTr) in the Xfer_S and the Xfer_D can be reduced.

Further, without wastefully applying a high voltage on the gates of theMOS transistor groups, the life of the peripheral circuit 20 can beextended.

(6) Distance Between Adjacent Wirings can be Decreased.

As explained in the above, the voltage supplied from the level shiftersLS is a low voltage. Therefore, the voltage condition between thewirings is relaxed. That is, in the case of a high voltage, the shorterthe inter-wiring distance is, the more likely that a wiring will beaffected by the voltage of an adjacent wiring (e.g., by capacitivecoupling). Therefore, it is necessary to increase the distance betweenadjacent wirings.

However, in the case of the nonvolatile semiconductor memory deviceaccording to the third embodiment, since the voltage is low, thedistance between adjacent wirings can be decreased. That is, an overallarea reduction can be achieved.

While certain embodiments have been described, these embodiments havebeen presented by way of example only; and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the methods andsystems described herein may be made without departing from the spiritof the inventions. The accompanying claims and their equivalents areintended to cover such forms or modifications as would fall within thescope and spirits of the inventions.

Structure of the memory cell array is not limited as above description.A memory cell array formation may be as disclosed in U.S. patentapplication Ser. No. 12/532,030, the entire contents of which areincorporated by reference herein.

What is claimed is:
 1. A memory device, comprising: a plurality of blockunits each including a plurality of blocks, each block including aplurality of memory strings, each memory string including a firsttransistor, a first memory cell transistor, a second memory celltransistor, and a second transistor; a plurality of first select gatelines, each of the first select gate lines connected to a gate of acorresponding one of the first transistors in each block unit; aplurality of second select gate lines, each of the second select gatelines connected to a gate of a corresponding one of the secondtransistors in each block unit; a plurality of first word lines, each ofthe first word lines connected to gates of the first memory celltransistors of a corresponding one of the blocks in each block unit; aplurality of second word lines, each of the second word lines connectedto gates of the second memory cell transistor of a corresponding one ofthe blocks in each block unit; a plurality of transfer transistors, eachfirst select gate line, each second select gate line, each first wordline, and each second word line respectively having one end of atransfer transistor connected thereto; a plurality of block decodershaving a selection signal output line respectively connected to gates ofthe transfer transistors connected to one of the block units; and avoltage supply circuit having voltage supply lines connected to anotherend of the transfer transistor respectively connected to the firstselect gate lines and the second select gate lines of each of the blockunits.
 2. The memory device according to claim 1, wherein each blockdecoder is configured to send a first selection signal to the selectionsignal output line in response to a first address signal, and thevoltage supply circuit is configured to supply voltages to the voltagesupply lines in response to a second address signal.
 3. The memorydevice according to claim 1, wherein the first transistor, the firstmemory cell transistor, the second memory cell transistor, and thesecond transistor are arranged along a vertical direction from asemiconductor substrate upon which the memory device is disposed.
 4. Thememory device according to claim 1, further comprising: a peripheralcircuit and pad, wherein the block decoder is disposed between thetransfer transistors and the peripheral circuit and pad.
 5. The memorydevice according to claim 1, wherein each memory string further includesa back gate transistor.
 6. The memory device according to claim 5,wherein, in each memory string, the back gate transistor is disposedbetween a part of the memory cell transistors and a remaining part ofthe memory cell transistors.
 7. The memory device according to claim 1,wherein only one block decoder is provided for each of the block units.8. The memory device according to claim 1, wherein a total number ofblock decoders is less than a total number of blocks.
 9. A method forcontrolling a memory device including a plurality of block units, eachincluding a plurality of blocks, each block having a plurality of memorystrings, each memory string including a first transistor, a first memorycell transistor, a second memory cell transistor, and a secondtransistor, a plurality of first select gate lines, each of the firstselect gate lines connected to a gate of a corresponding one of thefirst transistors in each block unit; a plurality of second select gatelines, each of the second select gate lines connected to a gate of acorresponding one of the second transistors in each block unit; aplurality of first word lines, each of the first word lines connected togates of the first memory cell transistors of a corresponding one of theblocks in each block unit; a plurality of second word lines, each of thesecond word lines connected to gates of the second memory celltransistor of a corresponding one of the blocks in each block unit; aplurality of transfer transistors, each first select gate line, eachsecond select gate line, each first word line, and each second word linerespectively having one end of a transfer transistor connected thereto;a plurality of block decoders having a selection signal output linerespectively connected to gates of the transfer transistors connected toone of the block units; and a voltage supply circuit having voltagesupply lines connected to another end of the transfer transistorrespectively connected to the first select gate lines and the secondselect gate lines of each of the block units, said method comprising:sending a first selection signal to the selection signal output line andsupplying voltages to voltage supply lines to perform reading or writingoperations on one of the blocks from a block unit.
 10. The methodaccording to claim 9, wherein each block decoder is configured to send afirst selection signal to the selection signal output line in responseto a first address signal, and the voltage supply circuit is configuredto supply voltages to the voltage supply lines in response to a secondaddress signal.
 11. The method according to claim 9, wherein the firsttransistor, the first memory cell transistor, the second memory celltransistor, and the second transistor are arranged along a verticaldirection from a semiconductor substrate upon which the memory device isdisposed.
 12. The method according to claim 9, wherein the block decoderis disposed between the transfer transistors and a peripheral circuit ora pad.
 13. The method according to claim 9, wherein each memory stringfurther includes a back gate transistor.
 14. The method according toclaim 13, wherein, in each memory string, the back gate transistor isdisposed between a part of the memory cell transistors and a remainingpart of the memory cell transistors.
 15. The method according to claim9, wherein only one block decoder is provided for each of the blockunits.
 16. The method according to claim 9, wherein a total number ofblock decoders is less than a total number of blocks.